Web server Tips¶
PHP safe mode¶
PHP safe mode has to be turned off. It is deprecated and has been removed in
newer PHP versions. Verify its status with PHP Version and Information, and look for
safe_mode
on/off
. If it is on, then add this line to php.ini
to turn it off:
safe_mode = Off
Enable the SPDY / http_v2 protocol¶
If you want to enable SPDY for Apache please note the Known Issues of this module to avoid problems after enabling it.
Apache Tuning¶
Maximum number of Apache processes¶
An Apache process uses around 12MB of RAM. Apache should be configured so that the maximum number of HTTPD processes times 12MB is lower than the amount of RAM. Otherwise the system begins to swap and the performance goes down.
KeepAlive should be configured with sensible defaults¶
The KeepAlive directive enables persistent HTTP connections, allowing multiple requests to be sent over the same TCP connection. This reduces latency by as much as 50%. Especially in combination with the periodic checks of the sync client the following settings are recommended:
KeepAlive On
KeepAliveTimeout 100
MaxKeepAliveRequests 200
mod_gzip¶
mod_gzip
should be used because it speeds up the transfer of data and
helps to free server memory, and HTTP connections are closed faster.
MPM¶
Apache prefork has to be used. Don’t use threaded mpm
with mod_php
because PHP is currently not thread safe.
Hostname Lookups¶
# cat /etc/httpd/conf/httpd.conf
...
HostnameLookups off
Log files¶
Log files should be switched off for maximum performance.
Comment out the CustomLog
directive. Keep ErrorLog
to be able to track
down errors.